But a loss in a populous Democratic stronghold like California could lend credence to Trump’s claim that she is a weakened candidate.

“Clinton would like to go to the nominating convention with the wind at her back and tamp down the perception that she doesn’t excite Democrats,” said Rodell Mollineau, a Democratic strategist in Washington.

A Sanders victory will not clear the way to his nomination unless it triggers a defection by scores of superdelegates – party office-holders and officials – from Clinton’s camp, an unlikely outcome.